Generally, the invention relates to the monitoring of liquid levels and to the automatic pumping of such liquid as to thereby, generally, be capable of maintaining the level of such monitored liquid below a preselected maximum level, or when considered from yet another point of view, maintaining the level of such monitored liquid within a preselected range of levels. As will become apparent, even though the invention was first conceived in the course of desiring to solve the prior art problems as relate to boat and/or ship bilge pumping systems, the invention, as conceived, and as hereinafter more fully disclosed has applications to fields other than such bilge pumping systems. However, to better appreciate the significance of the invention, the background of the invention will be set forth as it applies to the heretofore prior art proposed bilge pumping systems.
As is well known and recognized, almost without exception, water craft and/or vehicles, for varying reasons, accummulate liquids in the bilge area. In some cases such liquid may be water while in other cases the bilge liquid may even be comprised of oil, gasoline or other substances, singly or in any combination, which may also be mixed with water. Often, such bilges also contain various bits of debris which may or may not float in the liquid but which is, nevertheless, movable therewithin.
Further, since the bilge is generally at the lower part of the hull (or body) of the water craft and since hulls are somewhat streamlined or otherwise non-uniform longitudinally along the keel, it is apparent that, for example, the same level of liquid along the length of the hull does not denote the same unit of volume of such liquid if measured at regular intervals longitudinally along the hull. In other words, the hull may be considered as a vessel of irregular configuration containing therein the bilge liquid. Consequently, if the hull is at rest and not moving with respect to the water, the level of the bilge liquid may be at a first elevation and span the entire distance from the stem to the stern; however, if the hull is then somewhat tilted as to have, for example, the stem or prow become relatively elevated, the level and relative attitude of that same quantity of bilge liquid will change and, quite possibly, will no longer span the entire distance from stem to stern.
Further, during operation of the water craft, the bilge liquid often undergoes sloshing due to, for example, the water craft executing turns or experiencing waves. This, in turn, causes the upper surface of the bilge liquid to rapidly and randomly change in configuration and relative location.
Heretofore, the prior art bilge pumping systems, which were considered to be automatic, employed such devices to float members to sense, by bouyant displacement, the presence of bilge liquid. Such float members, in turn, were employed to open and close related electrical switch means in order to thereby deenergize and energize electrical motor means for driving related pump means. However, as should be apparent, the prior art float members were totally responsive to level of the bilge liquid even if that level was momentary or a false indication of the actual quantity of bilge liquid carried by the water craft. That is, if the relative level and attitude of the bilge liquid was changed for a short period of time, as during turns, etc., the prior art float would respond to the resulting presence or absence of the bilge liquid and accordingly activate or de-activate the pumping means. The same situation would occur when the bilge liquid experienced sloshing.
Also, as the water craft experienced water or wave pounding and reacted as by rolling or pitching, the prior art float members would also become unstable, due to inherent inertia, again resulting in undesired activation and de-activation of related pumping means.
The prior art floats were often associated with related moving linkage means in order that relative motion of the float could be sensed as to thereby activate and de-activate associated pumping means. This raised other problems associated with dirt and corrosion which often prevented such linkage means from having the freedom of relative motion necessary to permit the float to move in response to changes in level of the bilge liquid.
Accordingly, the invention as herein disclosed is primarily directed to the solution of the foregoing as well as other related and attendant problems whether in the art of bilge pumping systems or in other applications of pumping and/or liquid level sensing systems.